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AOAC Official Method 2014.05
Enumeration of Yeast and Mold
in Food
3M
™
Petrifilm
™
Rapid Yeast and Mold Count Plate
First Action 2014
[Applicable to the enumeration of yeast and mold in the following high-water activity matrices: yogurt,
frozen bread dough, fermented salami, sour cream, ready-made pie, raw frozen ground beef patties
(77% lean), ready-to-eat deli sandwiches, sliced apples, and the following low-water activity matrices:
raw almonds and dehydrated soup.]
See
Tables
2014.05A
and
2014.05B
for a summary of results of the collaborative study. The result for
each collaborating laboratory’s aerobic plate count analysis for each matrix is shown in Table
2014.05C
.
See
Tables 2-9 in the
J. AOAC Int
. paper for detailed results of the collaborative study.
A. Principle
The 3M
TM
Petrifilm
TM
Rapid Yeast and Mold Count (RYM) Plate is a sample-ready culture medium
system, which contains nutrients supplemented with antibiotics, a cold-water-soluble gelling agent, and
an indicator system that facilitates yeast and mold enumeration. 3M Petrifilm RYM Count Plates are
used for the enumeration of yeast and mold in as little as 48 h in the food and beverage industries. 3M
Food Safety is certified to ISO (International Organization for Standardization) 9001 for design and
manufacturing.
B. Apparatus and Reagents
(
a
)
3M Petrifilm RYM Count Plate.
–25 plates/pouch; two pouches/box (3M Food Safety, St. Paul, MN,
USA).
(
b
)
Sterile diluents.-
-0.1% peptone water.
(
c
)
Pipets.-
-Capable of 1000 µL or a serological pipet.
(
d
)
Sterile pipet tips.-
-Capable of 1000 µL.
(
e
)
Stomacher.--
Seward or equivalent.
(
f
)
Filter stomacher bags.
--Seward or equivalent.
(
g
)
3M
TM
Petrifilm
TM
Flat Spreader.
(
h
)
Incubators.–
Capable of maintaining 25 ± 1°C and 28 ± 1°C and having a solid front to maintain a dark
interior.
(
i
)
Refrigerator.--
Capable of maintaining 2-8°C, for storing the 3M Petrifilm RYM Plates.
(
j
)
L-shaped spreaders.
(
k
)
Standard colony counter or illuminated magnifier.
Candidates for 2016 Method of the Year
68